Deicer heat distributing means



Feb. 28, 1950 R. B. PARK DEICER HEAT DISTRIBUTING MEANS 2 Shets-Sheet 1 Filed Nov. 3, 1945 INVENTOR Richard 5. Park BY am if M ATTORNEY.

Feb. 28, 1950 R. B. PARK DEICER HEAT DISTRIBUTING MEANS 2 Sheets-Sheet 2 Filed Nov. 3, 1945 v INVENTOR R/chard 5. Park ATTORNEY.

Patented Feb. 28, 1950 DEICER HEAT DISTRIBUTENG MEANS Richard B. Park, "West Hartford, Conn, assignor to United Aircraft Corporation, East Hartford, Conn, a corporation of Delaware Application November 3, 1945, Serial No. 626,502 2 Claims. (o1. 2444134) This invention relates to heating devices for raising the temperature of selected portions of propeller blades to facilitate removal of ice coatings and to prevent the formation of ice coatmgs.

An object of the invention is the provision of a heater strip adhesively secured to the propeller blade.

Another object of the invention is the provision of a heater in which the heat is greatest along the leading edge portion of the blade and gradually diminishes chordwise of the blade toward the trailing edge.

A further object of the invention is the provision of electrically energized heating means for heating a metal strip which provides a gradation of the heating from the leading edge rearwardly of the blade.

Other objects and advantages will be apparent from the specification and claims and from the accompanying drawings which illustrate what is now considered to be a preferred embodiment of the invention.

In the drawings,

Fig. 1 is a side elevation showing the general arrangement of the blades, the de-icer strips and their source of electricity.

Fig. 2 is a side elevation of a blade with the deicer strip applied.

Fig. 3 is a front elevation of the same blade.

Fig. 4 is an enlarged detail, with portions broken away of the interior of the leading edge strip before the rubber coating is applied.

Fig. 5 is a view taken along the lines Y-Y of Fig. 2.

Fig. 6 is a sectional view taken along the lines 65 of Fig. 2, and

Fig. 7 is an enlarged cross section of the blade leading edge with the heater strip applied.

The invention is shown as associated with a controllable pitch propeller having a hub it mounted on a shaft extending outwardly from an engine nose l2. Propeller blades it and 66 are supplied with metal leading edge portions 58 and 20 and have shank portions 22 and 24 ex- J tending into and rotatably supported by pro peller hub Ill. The metal leading edge strips l8 and 20 are electrically heated by electricity supplied from a generator having a stationary field portion 26 mounted on the engine nose and 1 excited by a suitable source of electricity, such as a storage battery, and a rotatable armature portion 28 mounted on and rotatable with the propeller hub It. Electricity is conducted from the armature 28 through slip rings 30 and 32 to heat- 55 ing wires on the inner surface of strips 13 and 2G. For a more detailed description of the generator, reference may be had to U. application Serial No. 474,684, filed February 1, 1943, of Edwin D. Eaton, for Propeller anti icer. Any other suitable source of electricity for heating strips may, of course, be used in place of that specifically described above.

The blades, one of which, it, is shown Fig. 2, may be made of metal such as aluminum and retained in the hub by the usual thrust bearings 34. The shank ends of the blades are covered with a fairing 556 which may be expanded rubber with a coating of neoprene .38. She blade may be made of other materials than aluminum. and the fairing may be made of the same material as the blade or other materials, but it is now preferred to apply a coating of neoprene or other suitable adhesive material to the blade at the portions where it is desired to secure the heater strip.

The heater strip [8 is a metal sheet, preferably aluminum, bent to conform to the leading edge portion of the blade. Heater wires til, preferably insulated Nichrome, are supported on the inner surface of the aluminum sheet by small strips of aluminum 42 spot welded to the strip it. The interior of strip 18, wires fill, and small supporting strips 42 are all coated with a layer of rubber 46 or other insulating adhesive which will provide a surface which can be cemented to the neoprene or other coating 38. The coated as sembly is then cemented or vulcanized onto the leading edge of the blade.

The heater wires extend longitudinally of the strip l8 and are spaced transversely to cover a material transverse area but much less than the width of the strip 58 so that in efi'ect they supply a concentrated heat source at the strip leading edge. The wires are shown as being threaded back and forth longitudinally of the strip 8 with the two ends of the wire secured to the aluminum strip and the center portion of the wire connected by one ofthe wires Ml to the generator. Heater wires it are, of course, insulated both from the aluminum strip 58 and the small holding strips 42 except where the heater wires are secured at their ends to the strip l8. One of the wires 54 connects the heater strip with one of the slip rings 3%! and the other Wire it connects the heater wire it with another of the slip rings 30.

The heater wires are thus embedded between the leading edge of the blade or its fairing and the strip [8. When the wires 40 are electrically heated, they will heat the strip I8, with the greatest amount of heat concentrated at the leading edge portion. Strip i8 is constructed of good heat conducting material, such as aluminum, and the heat is, therefore, conducted throughout the strip, the quantity of heat and the temperature gradually diminishing from the leading edge rearwardly toward the side edges of strip l8. Such a construction is economical in that it will apply the greatest amount of heat where the greatest amount of heat is needed and gradually taper off that heat where less is required. The rubber coating 46 on the inside of the leading edge strip 58 serves as an insulating member and helps to prevent dissipation of heat into the blade and helps to confine the heat generated in the heater wires to the leading edge strip. If an adequate bond can be obtained, preferably by a cold cementing process, between the coating 46 and the blade or fairing material, the coating 33 on the blade may be omitted.

It is to be understood that the invention is not limited to the specific embodiment herein illusstrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

Iclaim:

1. In combination with a propeller blade, a heat conducting metal strip covering at least a portion of the leading edge of said propeller and extending rearwardly toward the blade trail-- ing edge, a concentrated heat source located at and extending along the blade leading edge between said strip and said blade for supplying heat to a concentrated zone at the leading edge oi said strip, said heat conducting metal strip distributing, b conduction rearwardly cho-rdwise of said blade, heat supplied by said concentrated source to the leading edge of said strip so that the temperature is highest at the leading edge and gradually reduces chordwise of said blade,

a layer of adhesive on the blade side of said metal strip and heat source, said adhesive securing said heat conducting metal strip to the leading edge portion of said blade and insulating said blade from heat radiated from said source.

2.1a combination with a propeller blade, a sheet of heat conducting metal curved to conform to the shape of and covering at least a portion of, the leading edge portion of said blade and extending rearwardly therefrom, electric heating wires extending longitudinally along and concentrated at the leading edge portion of said conformed sheet to provide a concentrated heat source, means for securing said heating wires on the concave side of said heat conducting strip to supply heat in a concentrated zone at the sheet leading edge, said heat conducting sheet distributing said heat rearwardly chordwise of said blade by conduction through said sheet from said concentrated zone so that the greatest amount of heat is supplied to the sheet leading edge and gradually reduces chordwise of said blade, a layer of adhesive on the concave surface of said unformed sheet and over said wires, said adhesive securing said heat conducting sheet to said blade and insulating said blade from heat radiated from said heating wires.

RICHARD B. PARK.

REFERENGES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,846,468 Benson Feb. 23, 1932 2,110,621 Cohen Mar. 15, 1938 2,309,682 Van Daam Feb. 2, 1943 2,406,367 Grifiith et a1 Aug. 27, 1946 2,454,874 Hunter Nov. 30, 1948 

